Error using the "GetDataList" command

Hello

I am fairly new to using C#. I have been using examples to create a GH component that uses Matlab code to evaluation. I manage to do this using items as inputs, but I want to use Lists as input. I am currently stuck when retreiving the data. I use the "GetDataList" command but I get the following error.

Any help is greatly appreciated

Replies to This Discussion

Permalink Reply by Andrew Heumann on April 14, 2017 at 7:47am

the problem is that the second argument to GetDataList has to be a List<T> which MWNumericArray presumably is not. You might need to retrieve a List<double> first (depending on the type of the param you're harvesting from) and then turn it into a MWNumericArray afterwards. Also, with GetDataList you do not need to use the "ref" keyword. So it should look like this:

List<double> i1 = new List<double>();

if(!DA.GetDataList(0, i1)) return;

Permalink Reply by Lasse Rahbek on April 14, 2017 at 1:05pm

OK thank you for the help! :)

Permalink Reply by Lasse Rahbek on April 14, 2017 at 1:16pm

So far so good! But turning List<double> into a MWNumericArray is apparently not that easy. I get the following error: Is it possible you know hot to convert a List<double> into MWNumericArray. I have tried different approaches but nothing have worked out yet.

Permalink Reply by Andrew Heumann on April 14, 2017 at 1:22pm

Here's a reference to the various ways of constructing an MWNumericArray: https://www.mathworks.com/help/dotnetbuilder/MWArrayAPI/html/T_Math...

There's some complexity as MWNumericArray appears to be able to support multi-dimensional arrays. I would maybe start here: https://www.mathworks.com/help/dotnetbuilder/MWArrayAPI/html/M_Math... and supply 1 for the row count and N for the column count where N is the number of items in your list. Then call ToArray() on your List<Double> and pass it as the realData argument. Not knowing anything about matlab or what you're trying to do, this is nothing more than a guess!

Permalink Reply by Lasse Rahbek on April 14, 2017 at 1:48pm

Great! I will look into it. Thank you for the help

Permalink Reply by Lasse Rahbek on April 15, 2017 at 2:17am

Just a follow up to others with the same problem. The following code will retrieve the data and convert it into MWNumericArray. After this the matlab component can take a list as input.